Jeep J-10 Series 1982 Technical & Service Manual page 137

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Valve Slit Refacing
Install a pilot of the correct size in the valve guide and
reface the valve seat to the specified angle with a dress
ing stone in good condition. Remove only enough metal
to provide a smooth finish. This is especially important
on exhaust valve seats. The seat hardness varies in
depth. Use tapered stones to obtain the specified seat
widths when required. Maximum seat runout is 0.0025
inch (0.064 mm) (fig. 1B-106).
41930
Fig. IB-106 Valve Seat Runout Measurement
Valve Stem Oil Deflector Replacement
Nylon valve stem oil deflectors are installed on each
valve stem to prevent lubrication oil from entering the
combustion chamber through the valve guide bores. Re
place oil deflectors whenever valve service is performed
or if the deflectors have deteriorated.
Oil deflector replacement requires removal of valve
springs. Refer to Valve Springs for procedure.
Valve Guides
The valve guides are an integral part of the cylinder
head and are not replaceable. When the stem-to-guide
clearance is excessive, ream the valve guide bores to the
next larger valve stem size. Service valves are available
with 0.003-inch (0.076 mm), 0.015-inch (0.127 mm) and
0.030-inch (0.760 mm) oversize stems.
Refer to the Valve Guide Reamer Size chart for listing
of reamers.
Valve Guide Reamer Sizes
Reamer
Tool Number
Size
J-6042-1
J-6042-5
J-6042^
0.003-inch (0.076mm)
0.015-inch (0.381mm)
0.030-inch (0.762mm)
60268
NOTE: Ream valve guide bores in steps. Start with the
0.003-inch (0.076 mm) reamer and progress to the size
required.
ENGINES 1B-71
Valve Stem-to-Gulde Clearance
Valve stem-to-guide clearance can be measured by
either one of two methods:
Preferred Method
(1) Remove valve from head and clean valve guide
bore with solvent and bristle brush.
(2) Insert telescoping gauge into valve guide bore
approximately 3/8 inch (9.525 mm) from valve spring
side of head (fig. 1B-107) with contacts crosswise to
head. Measure telescoping gauge with micrometer.
(3) Repeat measurement with contacts lengthwise
to cylinder head.
(4) Compare lengthwise and crosswise measure
ments to determine out-of-roundness. If measurements
differ by more than 0.0025 inch (0.0635 mm), ream guide
bore to accommodate oversize valve stem.
(5) Compare valve guide bore diameter measure
ment with diameter listed in Specifications. If measure
ment is larger by more than 0.003 inch (0.076 mm), ream
guide bore to accommodate oversize valve stem.
GAUGE
VALVE STEM
GUIDE
80303
Fig. 1B-107 Measuring Valve Guide Bore with Telescoping Gauge
Alternate Method
Use a dial indicator to measure the lateral movement
of the valve stem with the valve installed in its guide
and barely off the valve seat (fig. 1B-108). Correct clear
ance is 0.001 to 0.003 inch (0.025 to 0.076 mm).
Installation
(1) Thoroughly clean valve stems and valve guide
bores.
(2) Lightly lubricate stem and install valve in same
valve guide bore from where it was originally removed.
(3) Install replacement valve stem oil deflector on
valve stem.
(4) Position valve spring and retainer on cylinder
head and compress valve spring with compressor tool.
Install valve locks and release tool.
(5) Tap valve spring from side to side with light
hammer to seat spring properly on cylinder head.